chapter 13 Amines Class 12 Chemistry Textbook Solution

3. Answer the following

v. Write a short note on coupling reactions.


i. Azo Compounds Formation:

  • Arenediazonium salts can react with certain reactive aromatic compounds like phenols or aromatic amines to produce azo compounds.

ii. Azo Coupling:

  • Azo compounds have an extended conjugated system of double bonds where two aromatic rings are connected through the azo group (-N=N-). This reaction is known as azo coupling.

iii. Brightly Colored Dyes:

  • Azo compounds are known for their vibrant colors and are commonly used as dyes.

iv. Electrophilic Aromatic Substitution:

  • This reaction exemplifies an electrophilic aromatic substitution process, with the electrophiles being positively charged diazonium ions.

v. Para Substitution:

  • Substitution typically occurs at the para position to the activating group on the aromatic ring.


  • For instance, when benzenediazonium chloride reacts with phenol in a mildly alkaline environment, it yields p-hydroxyazobenzene, an orange dye.

vi. Confirmatory Test for Primary Aromatic Amines:

  • Azo coupling with β-naphthol in the presence of NaOH is often employed as a confirmatory test for primary aromatic amines.

vii. Formation of p-Aminoazobenzene:

  • When benzenediazonium chloride reacts with aniline in a mildly alkaline environment, it results in the formation of p-aminoazobenzene, a yellow dye.

13 Amines Class 12 Chemistry Textbook Solution page 297